Genetics Mastering Chapter 2

Which of the following are areas where chromatids intertwine during meiosis?

Chiasma

Name two cellular organelles, each containing genetic material, which are involved in either photosynthesis or respiration.

Chloroplasts and mitochondria

What significant genetic function occurs in the S phase of the cell cycle?

DNA synthesis

Cells that are metabolically active, but not destined to proliferate are said to be in _____.

G0 phase

During which stage can cells either exit the cell cycle or become committed to completing the cell cycle?

G1

If a typical somatic cell has 64 chromosomes, how many chromosomes are expected in each gamete of that organism?

32

The diploid chromosome number of an organism is usually represented as 2n. Humans have a diploid chromosome number of 46. What would be the expected haploid chromosome number in a human?

23

The house fly, Musca domestica, has a haploid chromosome number of 6. How many chromatids should be present in a diploid, somatic, metaphase cell?

24

A _____ chromosome has its centromere located very close, but not on, the end of the chromosome.

Acrocentric

Which chromosome has a telomere but the p arm is much shorter than the q arm?

Acrocentric

The centromere of a chromosome separates during _____.

Anaphase

During meiosis, chromosome number reduction takes place in ___.

Anaphase I

When do sister chromatids separate during meiosis?

Anaphase II

The accompanying sketch depicts a cell from an organism in which 2n = 2 and each chromosome is metacentric. Which of the following is the correct stage for this sketch?

Anaphase of meiosis II.

During interphase of the cell cycle _____.

DNA content essentially doubles

Living organisms are categorized into two major groups based on the presence or absence of a nucleus. What group is defined by the presence of a nucleus?

Eukaryotic organism

The longest stage of interphase is G2.

False

Electron microscopy of metaphase chromosomes demonstrated various degrees of coiling. What was the name of the model that depicted this process?

Folded-fiber

When cells withdraw from the continuous cell cycle and enter a "quiescent" phase, they are said to be in what stage?

G0

Checkpoints are points between phases of the cell cycle at which a cell determines whether all the requirements necessary for each phase of the cell cycle have been properly satisfied. For example, because a cell with damaged DNA can lead to cancer if it's allowed to divide, a cell with damaged DNA usually arrests the cell cycle until the damage can be repaired. At which phase(s) of the cell cycle would a cell normally check for the integrity of its DNA?

G1/S and G2/M phases

The stage at which "sister chromatids go to opposite poles" immediately follows which of the stages listed below?

Mitotic metaphase and metaphase of meiosis II

After meiosis II, _____ would be formed.

Monads

Which of the following statements about meiosis is true?

The chromosomes number is reduced by one-half

During which stage of prophase I does crossing over take place?

Pachynema

Which of the following is not a source of genetic variation in meiosis?

Polar body formation

Which condition is evaluated at the G2/M checkpoint?

Precise replication of DNA

Which term describes meiosis I?

Reducational

The nucleolus organizer region (NOR) is responsible for production of what type of cell structure?

Ribosome

Which of the following cell structures is directly involved in protein synthesis?

Rough endoplasmic reticulum and ribosomes

Which part of interphase does DNA duplication take place?

S

The ant, Myrmecia pilosula, is found in Australia and is named bulldog because of its aggressive behavior. It is particularly interesting because it carries all its genetic information in a single pair of chromosomes. In other words, 2n = 2. (Males are haploid and have just one chromosome.) Which of the following figures would most likely represent a correct configuration of chromosomes in a metaphase I cell of a female?

SEE NOTES

What is the outcome of synapsis, a significant event in meiosis?

Side-by-side alignment of homologous chromosomes

What is the arrangement of chromosomes during metaphase?

Sister chromatids align along the equatorial plane of the cell

Which of the following is true about the second meiotic division?

Sister chromatids are pulling apart

In humans, what is a fundamental difference between the production of female gametes and male gametes?

The production of female gametes but not male gametes involves an unequal division of cytoplasm

Which of the following is true about sex-determining chromosomes?

They act like homologous chromosomes during meiosis so each gamete will get one sex chromosome

A tetrad is composed of one pair of homologous chromosomes at synapsis of prophase I.

True

The meiotic cell cycle involves ____ number of cell division(s) and _____ number of DNA replication(s).

Two; one